Testing Quantum Entanglement...

Nacho: Your explanations on the previous page look spot-on to me. In particular, it's worth re-emphasizing that entanglement can only be inferred by looking at statistical ensembles of identically prepared systems; there exists no measurement that will tell you whether a single pair of particles is entangled. Similarly, when a measurement on one half of an entangled pair collapses the wavefunction, there is no measurement on the other than can indicate a collapse has occurred. Only by comparing the measurement results on both halves can we see that quantum weirdness is occurring. One consequence of this is that quantum entanglement does not allow faster-than-light communication; I could try to send a signal by measuring an entangled particle to collapse its partners wavefunction, but to receive my signal, someone on the other side would have to determine whether the wavefunction had collapsed using only one particle, which is impossible.

Also, Joy Christian is a well-intentioned but misguided fellow who got lost in the complexity of his own math. Bell's Theorem is one of the most interesting results in all of quantum mechanics.

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I don't feel that strongly about entanglement. It is what it is. What force or mechanism do YOU think holds the fundamental particles of atomic structure into local packets of energy that do not change their internal structure over time, or simply radiate off into empty space? What force can act fast enough to sculpt electrons in every direction at once into perfectly round identical spheres?

Do you have any science knowledge of anything at all that is capable of doing something like that? Please explain it. If your answer is a deity, we will all then understand where you are coming from.

Bell did not imagine entanglement in this way, really, did he? What "hidden variable" is responsible for this local behavior of bound energy? What binds it, EXACTLY?

There was some discussion years ago about opening a sub forum called philosophy of science ( math and physics) perhaps the dialogue misled you at the time...
It did not eventuate as most issues were resolved more or less in one thread... hee hee and finer logic and reason is notoriously hard to discuss properly over public web based forums.

I don't feel that strongly about entanglement. It is what it is. What force or mechanism do YOU think holds the fundamental particles of atomic structure into local packets of energy that do not change their internal structure over time, or simply radiate off into empty space? What force can act fast enough to sculpt electrons in every direction at once into perfectly round identical spheres?

Do you have any science knowledge of anything at all that is capable of doing something like that? Please explain it. If your answer is a deity, we will all then understand where you are coming from.

Bell did not imagine entanglement in this way, really, did he? What "hidden variable" is responsible for this local behavior of bound energy? What binds it, EXACTLY?

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If I knew that I would most likely get a Nobel Prize (or, if anybody else knew that they would get one). As strongly as you feel negatively about entanglement, I feel strongly that superposition is bunkum, and certainly not a physical event.

The whole subject of quantum entanglement is fascinating to me... it led me to the test statement (delta t=0 then d=0**) which logically provides a connecting mechanism and a few other solutions hard sort after.
**meaning if the duration of time is zero then distance must also be zero.

Controversially:
So at any given moment, say mark 10 am, distance is zero.Hypothetically:
It is only when duration ( time) is present that entanglement is not available to be tested for a given set of half particles. Entanglement is still present but can not be verified.
There's a lot more to it but this is not the fora to discuss it... sorry for the aside...

If I knew that I would most likely get a Nobel Prize (or, if anybody else knew that they would get one). As strongly as you feel negatively about entanglement, I feel strongly that superposition is bunkum, and certainly not a physical event.

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I tend to ignore Bell's Theorem (not entanglement) as 'bunk', in the sense that it is the theorem that is dismissive of entanglement.

Interesting that you are skeptical of superposition, which I have always taken as a given pretty much because for most of my career, I was a telecom engineer and for them it is like breathing.

Two beams of light at right angles pass right through each other without either one affecting the other. This happens because superposition just works. Same thing happens with ten layers of modulation for telecommunication. Superposition is just adding (or later subtracting) independent modulating components vectorially. So, what's the issue with superposition?

The whole subject of quantum entanglement is fascinating to me... it led me to the test statement (delta t=0 then d=0**) which logically provides a connecting mechanism and a few other solutions hard sort after.
**meaning if the duration of time is zero then distance must also be zero.

Controversially:
So at any given moment, say mark 10 am, distance is zero.Hypothetically:
It is only when duration ( time) is present that entanglement is not available to be tested for a given set of half particles. Entanglement is still present but can not be verified.
There's a lot more to it but this is not the fora to discuss it... sorry for the aside...

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I remember the Zeno paradox thread. Even though it went nowhere in particular, this is the paradox where Peter Lynde's ideas about the nature of time began.

His ideas are all front and center, and spot on, as far as I am concerned. He was the first one to observe, freezing an instant of time like a freeze frame image may be easy to do mathematically, or mechanically, but also instantly robs the universe of inertia, and the idea that time does not exist for something like a photon is something as stupid as believing that a single frame of a pulse of light passing through a Coca Cola bottle taken with a femtosecond camera is anything but a 2D symbol representing an instant in time that was over a femtosecond after it was taken.

Time doesn't 'stop' at a relative velocity of c. Light would cease to propagate if it did. The error was Minkowski, because he is the idiot who, for the purposes of Special Relativity, set time itself as proportional to the speed of light. This is what happens when you divide by zero and expect no one will notice because the universe is sourced by something that is inside your head, like many other delusions. Or that Zeno or Achilles can stop and start moving again when he has approached within half a Planck length light travel time from reaching the turtle. Might actually break his ankle, trying to do that. If the turtle was entangled, Achilles lost the race before it was even begun. What if Achilles could run close enough to c? Time means something distinctly different for the speedy unbound energy of a photon vs the bound energy of that old turtle.

Following Minkowski's lead, some particle physicists also believe that something like the Higgs mechanism can actually source inertial mass for some parts of atomic structure and not others, and sidestepping both the law of the conservation of mass/energy and what little we know about quantum entanglement, they can do so without also imparting gravitational mass, which arrives in the universe by the good graces of an as yet undiscovered but much lighter particle known as the graviton, which has spin 2. The Higgs is the only particle with spin zero, and imparts inertial mass to electrons with +/- half integer spin. Did you know, there is a distinct difference between spin inertia and Galileo's, commemorated in Newton's first law? Why do you think that might be the case? Inertia isn't nearly as classical as Ancient Greek geometry.

High on too much phlogiston, perhaps? I couldn't dream a more bizarre and obtuse theory (the graviton) if I tried really hard. Does anyone think people so challenged to conceptualize anything other than the math they idolize, really understand something as tangible and real as "inertia"? If it doesn't come from first mathematical principles, that is. I'm only saying...

I've just come to that conclusion from what I've read, that superposition(*1) is just a mathematical treatment, no physics involved. I think Dirac does a very good writeup on it in his book: The Principles of Quantum Mechanics.

Suppose you know that one spouse of a heterosexual couple is arriving on a space ship, train, or airplane. When you discover that the arriving spouse is female you immediately know that the distant spouse is male.

Is the above mysterious or some violation of locality? Has FTL communication occurred?

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I think the situation with married couples is exactly analogous to the situation with entangled particles.

I wanted you to show me the recent examples, not mentioned by Christian, which "more or less" contradict Bell's theorem.

danshawen said:

Bell's theorem, as stated, is unfalsifiable. This means it is not science. I can't make it any plainer than this.

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More disconnection. You believe Christian has disproved Bell's theorem, how can that be possible?

But Bell's theorem is falsifiable: a single counterexample is all that's needed. The theorem is scientific, and moreover, is not about quantum mechanics specifically. It's about what physical theories can be and what they can define, in a way.

p.s. entanglement, superposition, and interference are what quantum computers use to compute numbers. If none of them are physically real, what could possibly be computed, why bother trying?
You could object that numbers aren't physically real either, any computer just ends up in some state after some time, so numbers are just interpretations of states.

p.s. entanglement, superposition, and interference are what quantum computers use to compute numbers. If none of them are physically real, what could possibly be computed, why bother trying?
You could object that numbers aren't physically real either, any computer just ends up in some state after some time, so numbers are just interpretations of states.

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I agree with the sentiment of your post, ... but ... you haven't established yet that quantum computers do work. I don't think it has been. There is noise around that they do, but nothing concrete that I know of.

Hmm. One issue of contention around right now is whether D-Wave has really built a quantum computer.

If they have, it should be capable of solving certain problems more efficiently, i.e. faster.
There are quantum circuits, you can construct these on a lab bench, which perform elementary kinds of computation. Lastly, there are the corporations and conglomerates all pushing the limits of fabrication and trying to get a chip to market.

Part of the timeline has to include the fact that the electronics industry will need to re-tool significantly if the materials need to be changed. That is, there aren't many diamond-based fabrication lines around yet, graphene is a newcomer. If someone finds a way to use silicon so the re-tooling can be minimised--a manufacturing upgrade rather than a replacement--things could accelerate.

Apparently 2017 will be the year the chips start rolling out. Who can say, really? There are a lot more difficulties involved in making reliable qubits and having them interact in a stable--often very low temperature--environment. It will be a triumph for our technology if it does happen.

On the other hand, I've completely lost count of the number of times I've seen a headline like "Quantum computers a step closer", with a storyline about yet another "breakthrough".

I've seen it written that Bell's theorem is to quantum information science as Shannon's theorem is to classical information science.

Quantum computers, in that sense, depend on Bell's inequalities being violated or not.
You can kind of relate in an intuitive way how uncertainty affects computation in a real, physical machine, but this set of inequalities seems to be about something else. But, maybe it's actually about the same thing--uncertainty about what is known about the state of some "system of particles". . .

Heisenberg's principle is possibly the most fundamental part of the "true" nature of space and time (plus whatever's in it).

So, then it is still not fully known if a quantum computer WILL work -- other than in their simulations?

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It depends how you define a computer, actually.

To be useful, a quantum computer will need dozens of qubits. That doesn't mean a 2-qubit system isn't a computer, it's just less capable than a 20-qubit computer. Arguably quantum communication algorithms are 'computed' by quantum computers of 2 or 3 qubits.

I've seen it written that Bell's theorem is to quantum information science as Shannon's theorem is to classical information science.

Quantum computers, in that sense, depend on Bell's inequalities being violated or not.
You can kind of relate in an intuitive way how uncertainty affects computation in a real, physical machine, but this set of inequalities seems to be about something else. But, maybe it's actually about the same thing--uncertainty about what is known about the state of some "system of particles". . .

Heisenberg's principle is possibly the most fundamental part of the "true" nature of space and time (plus whatever's in it).

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Yeah, but quantum computers rely on, what I think is dubious, superposition. From what I've read, they talk about it as a physical entity, and it is the very basis of their design. I asked some questions about quantum computers in my first post .. parts that I don't understand. In more detail they were:

1) Say they have 4 qubits lined up that they want to put into (what they call) a superposition of states, so that a computation can take place. How do they know the bits are in that superposition? If they find out, doesn't that itself disturb the superposition?

2) How do they come out of that superposition? Doesn't that take a measurement to do that? And if it takes a (physical) measurement, how are they to know when the proper time is to take that measurement? (maybe it doesn't matter when??)

3) Trying to get some communications (computation) out of superposition kind of smacks me of the same as trying to get FTL communications out of entangled particles. That is, you can get information/communications out of entangled particles, but it requires a person to go over the results AFTER the experiment takes place, and it would result in communications at a speed less than the speed of light. What I'm wondering here, is that if it possible that they may get some information out of the quantum computer, but it would come from statistical analysis of the data AFTER the qubit computations took place, and thus result in computations that are slower than a regular computer. Quantum Mechanics seems to do everything it can to not let us know its full secrets (if there are any, that is).